If your plan was just to migrate directly from one set of discs to another, the quick and dirty way would be to just dd the image from one drive to another.
However, if you're planning on changing your boot drive from a single XFS drive to a mirrored ZFS setup, you're better off doing a fresh OS install on the new drives in a mirrored ZFS configuration, and the restoring the relevant part of the install (e.g. /var and most of /etc) from backup in to the new OS.